The maintenance of a substantially constant bath level is important for the purpose of controlling the quality of an ingot, especially with continuous casting. Thus, the rate of supply of fresh molten metal and/or the extraction speed of the ingot should be controlled in a manner compensating for deviations from the desired level.
Conventional methods of detecting such a bath level in an ingot mold involve temperature measurements, supersonic soundings, or the transmission of radioactive particles through the vessel wall. These techniques must be specifically adapted to the given mold configuration and frequently require the emplacement of fragile sensors in the immediate vicinity of the inflow.